title: A new Stenotrophomonas maltophilia strain producing laccase. Use in decolorization of synthetics dyes.
abstract: Laccase activity was detected in a soil bacterium Stenotrophomonas maltophilia AAP56 identified by biochemical and molecular methods. It was produced in cells at the stationary growth phase in Luria Bertani (LB) medium added by 0.4 mM copper sulfate. The addition of CuSO(4) in culture medium improved production of laccase activity. However, one laccase enzyme was detected by native polyacrylamide gel electrophoresis. The enzyme showed syringaldazine (K (m) = 53 microM), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (K (m) = 700 microM), and pyrocatechol (K (m) = 25 microM) oxidase activity and was activated by addition of 0.1% (v/v) Triton-X-100 in the reaction mixture. Moreover, the laccase activity was increased 2.6-fold by the addition of 10 mM copper sulfate; the enzyme was totally inhibited by ethylenediaminetetraacetic acid (5 mM), suggesting that this laccase is a metal-dependant one. Decolorization activity of some synthetic dyes (methylene blue, methyl green, toluidine blue, Congo red, methyl orange, and pink) and the industrial effluent (SITEX Black) was achieved by the bacteria S. maltophilia AAP56 in the LB growth medium under shaking conditions.
authors.affiliation: Biological Engineering Unit 99UR09-26, National Institute of Applied Sciences and Technology, North Urban Center, B.P. 676, 1080 Tunis, Tunisia.
authors.forename: Said
authors.initials: S
authors.lastname: Galai
authors.forename: Ferid
authors.initials: F
authors.lastname: Limam
authors.forename: M Nejib
authors.initials: MN
authors.lastname: Marzouki
mesh_terms: D004396:Coloring Agents / Q000378:metabolism*; D042845:Laccase / Q000096:biosynthesis* / Q000378:metabolism*; D020615:Stenotrophomonas maltophilia / Q000201:enzymology*
chemical_list: D004396:Coloring Agents; D042845:Laccase